2009 Volvo C30 Owner's Manual - Page 167

07 Wheels and tires General information Tread wear indicator New Tires Remember that tires are perishable goods. As of 2000, the manufacturing week and year (Department of Transportation (DOT) stamp) will be indicated with 4 digits (e.g. 1502 means that the tire illustrated was manufactured during week 15 of 2002). • Tire wear increases with speed. • Correct front wheel alignment is very important. • Unbalanced wheels impair tire economy and driving comfort. • Tires must maintain the same direction of rotation throughout their lifetime. • When replacing tires, the tires with the most tread should be mounted on the rear wheels to reduce the chance of oversteer during hard braking. Tire age Tires degrade over time, even when they are not being used. It is recommended that tires generally be replaced after 6 years of normal service. Heat caused by hot climates, frequent high loading conditions or Ultra Violet (U.V) exposure can accelerate the aging process. You should replace the spare tire when you replace the other road tires due to the aging of the spare. A tire's age can be determined by the DOT stamp on the sidewall (see the illustration). A tire with e.g., visible cracks or discoloration should be replaced immediately. G020323 • Hitting curbs or potholes can damage the tires and/or wheels permanently. The tires have wear indicator strips running across or parallel to the tread. The letters TWI are printed on the side of the tire. When approximately 1/16" (1.6 mm) is left on the tread, these strips become visible and indicate that the tire should be replaced. Tires with less than 1/16" (1.6 mm) tread offer very poor traction. When replacing worn tires, it is recommended that the tire be identical in type (radial) and size as the one being replaced. Using a tire of the same make (manufacturer) will prevent alteration of the driving characteristics of the vehicle. 07 Improving tire economy • Maintain correct tire pressure. For the tire pressure tables, see page 170. • Drive smoothly: avoid fast starts, hard braking and tire screeching. 167